Affirmative form of the sentence: There doesn’t seem to be anybody in the office.
There seems to be somebody in the office.
Affirmative form of the sentence: He doesn’t know anything about the plan.
He knows something about the plan.
Negative form of the sentence: You left something on the hall table.
You left nothing on the hall table. / You didn't leave anything on the hall table.
Affirmative form of the sentence: There isn’t anything the matter with Toby’s ear.
There is something the matter with Toby's ear.
Affirmative form of the sentence: We haven’t spoken to anybody about it.
We have spoken to somebody about it.
Affirmative form of the sentence: There wasn’t anyone at the door.
There was someone at the door.
Negative form of the sentence: I lost the book somewhere downtown.
I lost the book nowhere downtown. / I didn't lose the book anywhere downtown.
Negative form of the sentence: He told us something about his trip.
He told us nothing about his trip. / He didn't tell us anything about his trip.
Negative form of the sentence: There is someone at the door.
There is no one/nobody at the door. / There isn't anyone/anybody at the door.
Negative form of the sentence: Bob will bring someone with him.
Bob will bring no one with him. / Bob won't bring anyone with him.